#!/bin/bash
#Program:
#	This program shows "Hello World!" in your screen.
#History:
#20171113	zhouxh	v1
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH


echo "This program will try to calculate:"
echo "How many days before your demobilization date..."
read -p "Please input your demobilization date (YYYYMMDD ex> 20150716: " date2

date_d=$(echo ${date2} | grep '[0-9]\{8\}')	# 看看是否有8个数字
if [ "${date_d}" == "" ]; then
	echo "Your input the wrong date format..."
	exit 1
fi

# 开始计算日期
declare -i date_dem=$(date --date="${date2}" +%s)	# 退伍日期秒数
declare -i date_now=$(date +%s)				# 现在日期秒数
declare -i date_total_s=$((${date_dem}-${date_now}))	# 剩余秒数统计
declare -i date_d=$((${date_total_s}/60/60/24))		# 转为日数
if [ "${date_total_s}" -lt "0" ]; then
	echo "You had been demobilization before: " $((-1*${date_d})) " ago"
else
	declare -i date_h=$(($((${date_total_s}-${date_d}*60*60*24))/60/60))
	echo "You will demobilize after ${date_d} days and ${date_h} hours."
fi
